Our definition of student net earnings may seem strange since tuition and other direct costs are not usually subtracted from "gross" earnings. Note, however, that indirect school costs are implicitly subtracted, for otherwise earnings would have to be defined as the sum of observed and foregone earnings, and foregone earnings are a major cost of high.school, college, and adult schooling. Moreover, earnings of on-the-job trainees would be net of all their costs, including direct "tuition" costs. Consistent accounting, which is particularly important when comparing earnings of persons trained in school and on the job, would require that earnings of students be defined in the same way.28 Regardless of whether all costs or merely indirect costs are subtracted from potential earnings, schooling would have the same kind of implications as general on-the-job training. Thus schooling would steepen the age-earnings profile, mix together the income and capital accounts, introduce a negative relation between the permanent and current earnings of young persons, and (implicitly) provide for depreciation on its capital. This supports my earlier assertion that an analysis of on-the-job training leads to general results that apply to other kinds of investment in human capital as well.